I think my alternator is crapping out because my volt meter in the dash was around 12v insted 14v. I know when a alternator isnt charging, its the diode. If I have to replace the Diode, should I get one with the largest amps possible for more output back to the battery because of other electronics that drain the battery, or a better voltage regulator?

What would I need to make my alternater charge my battery better?

 

A failed diode in the rectifier bridge may cause undercharging. A failing or poorly connected regulator can do the same thing. Poor brush/slip ring contact can also lower alternator output. A slipping belt, loose sheave, failing stator, or grounding field can also do that. You really need to diagnose a bit more before arriving at a conclusion. Even dirt and carbon accumulation around the slip rings can lower alternator output.

As for increasing output, if the alternator is operating in peak condition, it should be able to deliver its full rated output at about 2,500 engine RPM and higher. If you need more output, you can install a heavy duty stator winding set rated for more current.